Sinusoidal gearing



Jan. 30, 1923.

H. J. EBERHARDT. SINUSOIDAL GEARING. FILED JAN 10. I920.

Fig-l Fig2 f/EW/ Ifii mnmm A TTOR/VEY Patented Jan. 30, 1923.

HENRY 3'. EBERHARDT, OF NEWARK, NEW! JERSEY, ASSIGNOR TO NIEl/VABK GEA'R CUTTING IIIACHINE (30., OF NEWARK,.1 TEW JERSEY,-

JERSEY.

A CORPORATION O'i NEW srnosornan ear-rains.

Application filed January 10, 1920. Serial N0.. 350,G14.

T 0 all ii /10m it may concern .1

Be it known that I, HENRY Jullnnnnannr, a citizen ofthe United States, and a resident of Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Sinusoidal Gearing, of which the following is a speci fication.

The invention relates to helical type gear ing, either single or double, and operative about axes substantially parallel to each other. Heretotore, various angles have been given the teeth of helical gearing to afi'ord continuity of tooth contact between a pair of gears on their pitch cylinders. The greater the angle used, the greater are the end thrusts and the longer is the time required for the cutting of the teeth; also, there re sults a greater deviation from standard spur gear proportions.

By means of the novel tooth construct-ion forming the subject of the present invention, 1 am enabled to provide a gear which can be readily cut, for example by the process set forth in my co-pending application, Serial No. 3eiS,958 filed the 2nd day of January 1920, and which provides greater strength of tooth for a given angularity and allows also for greater continuity of pitch line tooth contact for a given average: The novel teeth which I term a n gularity. A sinusoidal is of a continuously varying angularity upon both sides of the axis ot the gear and approximates in contour that of a true helix, being, however, of greater angularily in relation to the axis at. opposite sides of the tooth CGIDIGL' The novel gear has teeth of greater continuity oi pitch line tooth contact for angularity, is more quickly and more easily out, and its construction, moreover, is conduct-ire to a more quiet gear operation at high speeds, for the decreasing and again increas ing angularity of the sinusoidal teetlrteuds to destroy the noisy vibration which is treuently set up with regularly formed teeth. I bsence of such vibration, tends to make the improved gears especially valuable in airplane, automotive and other high speed transmissions. While the teeth are herein shown and described constructed on cylindrical pitch surfaces, it is obvious that the same may be applied to an elliptical sura given averagev face and also that they may be employed as rack teeth. a rack of this character being a sinusoidal gear wheel of infinite radius.

The accompanying, drawings illustrate diagra-mmatically the novel teeth as variously constructed on cylindrical pitch surfaces; and inthese drawings, I

Fig. 1 is a top view illustrating the outlines of teeth embodying my invention and as applied to a single wheel.

Fig. 2 is a similar view illustrating the invention as applied to a double herringbone gear wheel, provided with a groove for cutting-tool clearance.

Fig. 3 is similar view of a double herring-bone gear wheel with clearance groove omitted. 1

The teeth and the various wheels shown may be cut by hobs, endmills, planing tools or other means and preferably by the method more particularly set forth in my aforesaid co-pending application; and the character of the teeth cut may be of any well-known type such as involute, or cycloidal.

Referring more particularly to Fig. 1 of the drawings, the tooth outline of a true helical tooth is indicated by the broken line (a) which represents a tooth having a uniform lead and angle of twist substantially as heretofore constructed. The novel tooth is represented in outline substantially by the full lines (6) which represent sinusoids of decreasing lead and increasing angle, the departure from the helix (a) being diagrammatically indicated by the space be tween the two lines (a) and It will be noted that the novel tooth has a continuously varying angularity upon opposite sides of the axis of the wheeL-the augularity first decreasing and then increasing as the tooth goes into action.

hen applied to gear wheels of the hen ringbone type, a plurality, for example two sets of sinusodial teeth may be arraugen as indicated in Fig. 2; and, ii" desired, a clearance groove may be provided between the same for the cuttin chipsmade by any preferred type of tool. 7

Or, the groove (0) may be entirely ornitted and a. double wheel formed with the two sets of teeth (a) adjoining. This latter type of herringbone gear with groove omitted, provides for greater strength and con pactness and is especially suited, to he cut with ewhnills or reciprocating planing tools.

l. claim 1. It. gear wheel, comprising a pitch surface parallel to its axis and sinusodial teeth thereon.

A gear wheel, comprising a pitch cylinder and. sinusoidal teeth. thereon.

A gear wheel, comprising a pitch surface parallel to its axis and helically oirected teeth thereon of continuously varying :mgularity upon opposite sides ot the axis.

A gear Wheel comprising a pitch surl ace parallel to its axis and helically directed teeth thereoin the angula-rity decreasing and again increasing as the teeth go into action.

5. A gear Wheeh con'iprising a pitch sur face parallel to its axis and a plurality of sets of oppositely directed sinusoidal teeth thereon.

(3. A gear Wheel, comprising a pitch cylinder and two sets of oppositely directed sinusoidal teeth thereon, the teeth of one set meeting substantially the spaces of the adjoining set at their common apex.

Signed at Newark in the county of Essex and State of New Jersey this 8th day of January A. D. 1920.

HENRY J. EBERHARDT. 

